Field emission structures have been utilized in a variety of ways to make use of their field characteristics. Such field characteristics have been used in tools for moving or aligning objects. For example, magnets have been used for moving metal sheets from a stack of metal sheets stacked on top of each other. Known magnets however do not provide granularity for controlling the number of sheets that could be picked up from the stack. A conventional magnet with a specific field emission characteristic may pick up all of the sheets on the stack when the application requires picking only one sheet on top of the stack. Accordingly, there exists a need for an emission field structure having an adjustable emission property that could accommodate various applications for movement or alignment of objects.